Railway track circuit apparatus



Oct. 31, 1939.

c R. PFLASTERER 2,178,287

RAILWAY TRACK CIRCUIT APPARATUS Original Filed April 28, 1957 INVENTOR AGeorge 18. lastepen BY i HIS ATTORNEY Patented Oct. 31, 1939 srs PAT

RAILWAY. TRACK CIRCUIT-APPARATUS Application April 28, 1937, Serial No.139,521 Renewed September 7, 1-938 1'7 Claims.

My invention relates to railway track circuit apparatus, and has for anobject the provision,

, in a track circuit including a track relay, of

means responsive to the application or removal of a track circuit shuntto compensate for changes in ballast resistance by automatically varyingthe value of the resistance between the source of track circuit energyand the track rails, in accordance with changes in ballast leakagecurrent so that the current received by the track relay will bemaintained substantially constant under wet and dry ballast conditions.

Since the compensating means will function upon an increase in the flowof current from one rail to the other due to a train shunt as well asupon an increase in such current due to a decrease in ballastresistance, another object of my invention is to provide apparatus,

' responsive only to the rapid application or reof its dry weather valuewhen the track circuit is occupied- I shall describe four forms ofapparatus embodying my invention, and shall then point out the novelfeatures thereof in claims.

-The railway track circuit apparatus embodying my invention is somewhatsimilar to that set forth in the copending application of Paul P.Sosinski, Serial No. 739,946, filed on August 15, 1934, for Railwaytrack circuit apparatus, and the said copending application containsclaims which cover broadly certain features of the invention describedin my present application.

In the accompanying drawing, Fig. l is a diagrammatic view showing oneform of apparatus embodying my invention. Figs. 2, 3, and 4 arediagrammatic views each showing a different modification of a portion-ofthe apparatus shown in Fig. l and each also embodying my invention.

Similar reference characters refer to similar parts in each of theviews.

Referring first to Fig. l, the reference characters. l and 2 designatethe-track rails of a stretch. of railway track'which are formed byinsulated joints 3 into a track section 5-6. The track section b t isprovided with'a track circuit which includes a track relay TR connectedacross the rails at one end of the section, and a source of energy, hereshown as a track battery B, at the other end of the section. Oneterminal of battery B is connected to one rail of the sectionby avariable resistor I, and the a other terminal is connected to the otherrail in series with a relay A andprimary winding 8 of atransformer T.Thereference character S designates a polarized relay comprising a U-shaped core 9 which is either a permanent magnet or is magnetized bymeans exterior to the core. Pivotally mounted at It in the backstrap ofthe core 9 is an armature l l which is arranged to oscillate between thetwo pole faces of the core, and which carries a winding 12 whichreceives energy from secondary'winding l3 of the transformer T. Thearmature N that contact l4l5 is closed when the armature H is swung tothe right, which I shall term its normal position, and'contact lil5 isopened when this armature is swung to the left or reverse position. as a.last position" relay, that is, armature H,

when deenergized, remains in the position to" which it was last operateduntil energized again in the opposite direction.

Variable-resistor l is so adjusted that the current supplied to therails by battery'B in dry relay A will cause this relay to become pickedup to close an auxiliary circuit, in multiple with resistor l, todecrease the total resistance between battery B and the track rails sothat track relay TR will receive substantially the same amount of energyit received under dry weather conditions. The auxiliary circuit iseasily traced and includes front contact I6 of relay A, contact I 4-5 ofrelay S, and variable resistor l1. When the ballast dries out, theresulting increase in ballast resistance will decrease the currentthrough the winding of relay A to permit the relay to return to itsinitial condition so that the resistance between battery B and the trackrails will be decreased to restore the track circuit current to its dryweather value. Such changes in the value of the current flowing inprimary. 8 of transformer T will be gradual in nature and will not,therefore, induce sulficient energy in secondary winding l3 to operaterelay S. 7

It will be apparent that since relay A becomes picked up upon anincrease in the value of the current supplied to the track circuit dueto a cooperates with a pair of contacts l4 and E5 in such a manner Therelay S is what is known decrease in ballast resistance, this relay willalso become picked up when the section 5-6 becomes occupied by a traindue to the shunting action of the wheels and axles of such train. Therapid increase in current, however, due to the train shunt, throughprimary winding 8 of transformer T will induce an impulse of reversepolarity in secondary winding l3 of transformer T so that armature ll ofrelay S will be caused to move to its reverse position to open contact Ill5. The opening of contact I l-45 breaks the previously tracedauxiliary circuit so that the resistance between the battery B and thetrack rails can not be reduced when the section 5-6 is occupied.Consequently, the release of the track relay TR will be more positivebecause this relay need be supplied with only sufficientenergy tomaintain the track relay picked up during dry weather conditions, andadditional energy can not be supplied to the track relay when the trackcircuit becomes occupied by a train.

When the train vacates section 5B, the sudden decrease in currentflowing in primary winding 8 of transformer T will induce an impulse ofnormal polarity in secondary winding I3 of transformer T so thatarmature II will be caused to move to its normal position, thusrestoring relay S to its initial condition.

Referring next to Fig. 2, the relay A is connected across the trackrails in multiple with the battery B and is, therefore, normallyenergized. The release value of relay A is so chosen that upon a givenincrease in the current supplied to the track circuit by battery B theresulting drop in potential across relay A will cause this relay tobecome released to establish an auxiliary circuit in multiple withresistor 1 so that the total resistance between battery B and the trackrails will be reduced. When the inter-rail current returns to its normalvalue relay A will, of course, become picked up to open the auxiliarycircuit. This auxiliary circuit includes back contact 18 of relay A,contact |4--l 5 of relay S and resistor H. The entrance and departure ofa train from section 5--6 will operate the relay S to govern theauxiliary circuit in a manner similar to that described for theapparatus shown in Fig. 1.

Referring next to Fig. 3, the reference character Bl designates anauxiliary track battery which supplies a portion of the track circuitcurrent through variable resistor l9 and relay A. Upon a given decreasein the ballast resistance, the relay A will become picked up by theincreased current flowing to the track circuit from battery Bl so thatfront contact iii of relay A will become closed to establish theauxiliary circuit in multiple with resistor I. In this view, however,contact l4--l5 of relay S is included in the circuit for relay A ratherthan in the auxiliary circuit. Otherwise the apparatus shown in Fig. 3operates in a manner substantially similar to that for the apparatusshown in Fig. 1.

Referring now to Fig. 4, auxiliary battery Bl is connected by variableresistor 19 and relay A in multiple with battery B and resistor I. Inthis view the auxiliary circuit is similar to that shown in Fig. 1, andincludes contact 14-45 of relay S and contact it of relay A, It isbelieved that detailed explanation of the apparatus in Fig. 4 isunnecessary because this will be apparent from an examination of thecircuits.

From the foregoing description of the apparatus embodying my invention,it will be seen that the shunting sensitivity of the track circuit forthe section 56 is increased because the track relay TR need not beexcessively overenergized during dry weather conditions to provide theenergy necessary to maintain the track relay efiectively energized in.wet weather. Furthermore, I have provided apparatus for automaticallypreventing any decrease in the resistance between the track battery andthe track rails when the section becomes occupied by a train so that thetrack relay TR can never receive energy in excess of the normal dryweather value with the track section occupied.

Although I have herein shown and described only four forms of apparatusembodying my invention, it is understood that various changes andmodifications may be made therein within the scope of the appendedclaims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a section of railway track having a pair of trackrails, a track circuit for said section including a track relay locatedadjacent one end of said section and receiving current from said trackrails, the track circuit including a source of energy located adjacentthe other end of the section for supplying current to said track rails,this source having one of its terminals connected to one of said trackrails and having its other terminal connected to the other of said trackrails in series with a resistor, an auxiliary relay energized from saidsource and occupying one or another control position as determined bythe amount of current flowing in said resistor due to the ballastresistance between the track rails, and another auxiliary relay alsoenergized from said source and responsive to changes in the value of thecurrent flowing in said track circuit, said other auxiliary relay havinga contact which is operative only in response to a rapid change in thevalue of such current, said auxiliary relays jointly controlling acircuit eiTective when the section is unoccupied and the ballastresistance is below a predetermined value for connecting said otherterminal of said source to said other track rail, said circuit includingsaid contact and shunting said resistor.

2. In combination, a section of railway track having a pair of trackrails, a track circuit for said section including a track relay locatedadjacent one end of said section and receiving current from said trackrails, the track circuit including a source of energy located adjacentthe other end of the section for supplying current to said track rails,this source having one of its terminals connected to one of said trackrails and having its other terminal connectedto the other of said trackrails in series with a resistor, an auxiliary relay energized from saidsource and occupying one or another control position as determined bythe amount of current flowing in said resistor clue to the ballastresistance between the track rails, another auxiliary relay alsoenergized from said source and responsive to changes in the value of thecurrent flowing in said track circuit, said other auxiliary relay havinga contact which is operative only in response to a rapid change in thevalue of such current, and a circuit effective when the section isunoccupied and the ballast resistance is below a predetermined value forconnecting said other terminal of said source to said other track rail,said circuit shunting said resistor and including contacts of both ofsaid auxiliary relays.

3. In combination, a section of railway track having a pair of trackrails, a track circuit ior having a pair oi track rails, a track circuitfor said section including a track-'relay located adjacent' one endofsaid section and receiving current fromsaid track" rails, the trackcircuit ineluding a sou-roe of energy located adjacent the other endofthe section for supplying current to said track rails, this sourcehaving one of its terminals connected to one of said track rails andhaving its other terminal connected to the other of said track rails inseries with a resistor, an auxiliary relay energized from said sourceand occupying one or another control position as determined by theamount of current flowing in said resistor due to the ballast resistancebetween the track rails, another auxiliary relay also energized fromsaid source and responsive to changes in the value of the currentflowing in said track circuit, said other auxiliary relay having acontact which is operative only in response to a rapid change in thevalue of such current, and a circuit effective when the section isunoccupied and the ballast resistance is below apredetermined value forshunting said resistor and by which said other terminal of said sourcemay be connected to said other track rail. said circuit includingcontacts of both of said auxiliary relays and having a resistor includedin series therewith.

4. In combination, a section of railway track having a pair of trackrails, a track circuit for said section including a track relay locatedadjacent one end of said section and receiving current from said trackrails, the track circuit including a source of energy located adjacentthe other end-of the section for supplying current to said track rails,this source having one of its terminals connected to one of said trackrails and having its other terminal connected to the other of said trackrails in series with a resistor, an auxiliary relay energized from saidsource and occupying one or another control position as determined bythe amount of current flowing in said resistor due to the ballastresistance between the track rails, and another auxiliary relay alsoenergized from said source and responsive to changes inthe value of thecurrent flowing in said track circuit, said other auxiliary relay havinga contact which is operative only in response to a rapid change in thevalue of such current, said auxiliary relays jointly controlling acircuit for connecting said other terminal of said source to said othertrack rail, said circuit shunting said resistor and including saidcontact and a resistor.-

5. In combination, a section of railway track said section including atrack relay located'adjacent one end of said section and receivingcurrent from said track rails, the track circuit inoi said track railaaresistor included in serieswith the connection between said otherterminal of said source and said other one of said track rails, anauxiliary relay having its winding con- 1 nected in series with theconnection between one terminal of said source and one of said trackrails, said relay having a contact which is open when the currentflowing in the relay winding is less than a predetermined Value, saidrelay contact being closed when the current flowing in the relay windingexceeds said predetermined value, another auxili'ary relay responsive tochanges in the value of the current flowing in said track circuit, saidrelay having a contact which is operative only in response to a rapidchange in the value of such current, and a circuit shunting saidresistor and by which said other terminal of said source may beconnected to said other track rail, said circuit including contacts ofboth of said auxiliary relays.

6. In combination, a section of railway track having a pairof trackrails, a track circuit for said section'- including a track relaylocated adjacent one end of said section and receiving current from saidtrack rails, the track circuit including a source of energy locatedadjacent the other end of said section for supplying current to saidtrack rails, said source having one of its terminals connectedto one ofsaid track rails and having its other terminal connected to the other ofsaid track rails, a resistor included in series with the connectionbetween said other terminal of said source and said other one of saidtrack rails, an auxiliary relay having its winding connected in serieswith the connection between one terminal of said source and one of saidtrack rails, said relay having a contact which is open when the currentflowing in the relay winding is less than: a predetermined value, saidrelay contact being closed when the current flowing in the relay windingexceeds said predetermined value, another auxiliary relay responsive tochanges in the value of the current flowing in said track circuit, saidrelay having a contact which is op-- era-tive only in response to arapid change in the value of such current, and acircuit shunting saidresistor and by which said other terminal of said source may beconnected to said other track rail, said circuit including contactsofboth of said auxiliary relays and having a resistor connected inseries therewith.

'7. In combination, a section of railway track having a pair of trackrails, a track circuit for said section including a track relay locatedadjacent one end of saidsection and receiving current from said trackrails, the track circuit including a source of energy located adjacentthe other end of said section for supplying current to said track rails,said source having one of its terminals connected to one of said trackrails and having its other terminal connected to the other of said trackrails, a resistor included in series with the connection between saidother terminal of said source and said other one of said track rails, anauxiliary relay having a winding, one terminal of said winding beingconnected to said one terminal of said source, the other terminal ofsaid winding being connected to said other terminal of said source inseries with said resistor, said relay having a contact which is openwhen and only when the current flowing in the relay winding exceeds apredetermined value, another I auxiliary relay responsive to changes inthe value of the current flowing in said track circuit, said relayhaving a contact which is operative only in response to a rapid changein the value of such current, and a circuit shunting said resistor andby which said other terminal of said source may be connected to saidother track rail, said circuit including contacts of both cfsaidauxiliary relays.

In combination, a section of railway track having a pair of track rails,a track circuit for said section including a track relay locatedadjacent one end of said section and receiving current from said trackrails, the track circuit ineluding a source of energy located adjacentthe other end of said section for supplying current to said track rails,said source having one of its terminals connecwd to one of said trackrails and having its other terminal connected to the other of said trackrails, a resistor included in series with the connection between saidother terminal of said source and said other one of said track rails, anauxiliary relay having a winding, one terminal of said winding beingconnected to said one terminal of said source, the other terminal ofsaid winding being connected to said other terminal of said source inseries with said resistor, said relay having a contact which is openwhen and only when the current flowing in the relay winding exceeds apredetermined value, another auxiliary relay responsive to changes inthe value of the current flowing in said track circuit, said relayhaving a contact which is operative only in response to a rapid changein the value of such current, and a circuit shunting said resistor andby which said other terminal of said source may be connected to saidother track rail, said circuit including contacts of both of saidauxiliary relays and having a resistor connected in series therewith.

9. In combination, a section of railway track having a pair of trackrails, a track circuit for said section including a track relay locatedadjacent one end of said section and receiving current from said trackrails, the track circuit including a source of energy located adjacentthe other end of said section for supplying current to said track rails,said source having one of its terminals connected to one of said trackrails and having its other terminal connected to the other of said trackrails, a resistor included in series with the connection between saidother terminal of said source and said other one of said track rails, anauxiliary relay having a winding, one terminal of said winding beingconnected to said one terminal of said source, the other terminal ofsaid winding being connected to said other terminal of said source inseries with said resistor, said relay having a contact which is openwhen and only when the current flowing in the relay winding exceeds apredetermined value, another auxiliary relay responsive to changes inthe value of the current flowing in said track circuit, said relayhaving a contact which is operative only in response to a rapid changein the value of such current, and a circuit shunting said resistor andby which said other terminal of said source may be connected to saidother track rail, said circuit being jointly controlled by both of saidauxiliary relays and having a resistor included therein.,

10. In combination with a section of railway track, a track circuitcomprising a track relay and a source of current therefor both connectedwith the rails of said section, a current-limiting device included inthe connection of said source with a rail of the section, an auxiliaryrelay energized by current which varies in accordance with the magnitudeof the ballast resistance between the rails of said section, anotherauxiliary relay energized from said source and responsive only to arapid change in the value of the current flowing in said track circuit,and a shunt path in multiple with said current-limiting device includinga contact of each of said auxiliary relays and effective upon apredetermined decrease in said ballast resistance for increasing thecurrent supplied to the track circuit from said source to therebycompensate for said decrease in the ballast resistance of said section.

11. In combination with a section of railway track, a track circuitcomprising a track relay and a source of current therefor both connectedwith the rails of said section, a current-limiting device included inthe connection of said source with a rail of the section, an auxiliaryrelay having its operating winding connected in series with said sourceand said current-limiting device, another auxiliary relay energized fromsaid source and responsive only to a rapid change in the value of thecurrent flowing in said track circuit, and means controlled by both saidauxiliary relays and efiective upon a predetermined decrease in theballast resistance for decreasing the efiective value of saidcurrent-limiting device to thereby increase the current supplied to thetrack circuit from said source so as to compensate for said deer-ease inballast resistance of said section.

12. In combination with a section of railway track, a track circuitcomprising a track relay and a source of current therefor both connectedwith the rails of said section, a current-limiting device included inthe connection of said source with a rail of the section, a firstauxiliary relay energized from said source and picked up or releasedaccording as the drop across said currentlimiting device is relativelylow or relatively high respectively as determined by the ballastresistance between the rails of said section, a second auxiliary relayalso energized from said source and responsive only to a rapid change inthe value of the current flowing in said track circuit, and a shunt pathin multiple with said current-limiting device including a contact ofsaid second auxiliary relay and a back contact of said first auxiliaryrelay, said shunt path being effective upon a predetermined decrease insaid ballast resistance, for increasing the current supplied to thetrack circuit from said source to thereby compensate for said decreasein the ballast resistance of said section.

13. In combination with a section of railway track, a track circuitcomprising a track relay and a main source of current therefor bothconnected with the rails of said section, a current-limiting deviceincluded in the connection of said source with a rail of the section, anauxiliary source of energy, means including the operating winding of anauxiliary relay for connecting said auxiliary source in multiple withsaid main source whereby said auxiliary relay will become operated bycurrent from said auxiliary source when the ballast resistance betweenthe rails of said section has a relatively low value, another auxiliaryrelay energized from said main source and responsive only to a rapidchange in the value of the current flowing in said track circuit, andmeans governed by said two auxiliary relays eflective when said ballastresistance has a relatively low value for closing a shunt path inmultiple with said current-limiting device to thereby increase thecurrent supplied to the track circuit from said main source in order tocompensate for the decrease in the ballast resistance of said section.

14. In combination with a section of railway track, a track circuitcomprising a track relay and a source of current therefor both connectedwith the rails of said section, a current-limiting device included inthe connection of said source with a rail of the section, a transformerconnected in series with said source and said currentlimiting device, anauxiliary relay energized from said source and occupying one or anothercontrol position. as determined by the amount of current vflowing insaid current-limiting device due to the ballast resistance between therails of said section, another auxiliary relay energized from saidtransformer and responsive only to a rapid change in the value of thecurrent flowing in said track circuit by way of said transformer, and ashunt path in multiple with said currentlimiting' device including acontact of each of said auxiliary relays and effective upon {apredetermined decrease in the ballast resistance for increasing thecurrent supplied to the track circuit from said source to therebycompensate for said decrease in the ballast resistance of said section.I

15. In combination with a section of railway track, a track circuitcomprising a track relay and a main sourceof current therefor bothconnected with the rails of said section, a current limiting deviceincluded in the connection of said source with a rail of the section, afirst auxiliary relay energized'from said main source and responsiveonly to a rapid change in the value of the current flowing in said trackcircuit, an auxiliary source of energy, means including the operatingwinding of a second auxiliary relay and a contact of said firstauxiliary relay for connecting said auxiliary source in multiple withsaid main source whereby said auxiliary relay will become operated bycurrent from said auxiliary source when the ballast resistance betweenthe rails of said section has a relatively low value, and a shunt pathin multiple with said current-limiting device including a contact ofsaid second auxiliary relay and efiective when said ballast resistancehas a relatively low value for increasing the current supplied to thetrack circuit from I said main source to thereby compensate for the Idecrease in the ballast resistance of. said section.

16. In combination with a section of railway track, a source of currentconnected withthe rails of said section, a current-limiting deviceincluded in the connection between said source andone rail of saidsection, a track relay receiving energy from the rails of the section,means connected with the rails of I said section and responsive to therateof change of the current supplied to the rails from said source,other means also connected with the rails of said section and energizedby current which varies in accordance with the magnitude of the ballastresistance between said rails, and means controlled by both saidaforementioned meansefiective upon a predetermined decrease in saidballast resistance for decreasing the effective value of saidcurrent-limiting device to thereby increase the current supplied to therails from said sourceso as to compensate for said decrease in theballast resistance of said section.

1'7. In combination. with a section of railway track, a track circuitcomprising a track relay ballast resistance between the rails of saidsection has a relatively low value, another auxiliary relay energizedfrom said main source and responsive only to a rapid change in the valueof the current flowing in said track circuit, and a shunt path inmultiple with said current-limiting device including a contact of eachof said auxiliary relays and eflective when said ballast resistance hasa relatively low valuefor increasing the current supplied to the trackcircuit from said main source to thereby compensate for the decrease inthe ballast resistance of saidsection.

GEORGE RQPFLAS'IERERQ

